The use of variable air volume (VAV) devices in order to control the temperature and/or ventilation in large buildings is wide spread. Such HVAC systems typically have at least one, and sometimes a plurality of VAV devices located in the various spaces, rooms or offices within the building for control of the discharge of conditioned air into the offices. The air typically will be provided by a central source, and the volume air discharged into each office within the building will be varied in accordance with the control mechanism for the VAV device. Such VAV devices typically have a damper or set of blades, which is moved by an actuator so as to change the area of the opening from which conditioned air is discharged from the VAV device. VAV boxes most typically are positioned upstream of a plurality of passive (damperless) air diffusers, while VAV diffusers include actuators and dampers at the structure discharging air into the space or office.
The control assembly for a VAV device will have one or more temperature set points which are used as a basis for regulating opening and closing of the damper by the actuator so as to drive the room temperature toward the set point. One set point may be used, for example, when the system is in a heating mode, while another may be used for a cooling mode. In some systems, however, the same temperature set point is used for heating and cooling.
In large office buildings, the HVAC system will be coupled to a plurality of thermostats located in the various offices or to a central building HVAC computer for monitoring and adjusting the set points for the VAV devices. In multiple thermostat systems, wiring must be run between individual VAV devices and the thermostats. In central computer systems, the computer is coupled through an HVAC building computer network that is coupled to the VAV devices. The central building control computer, therefore, can be used to monitor and adjust the set point temperatures of the various actuators in the VAV devices for individual offices.
One of the major disadvantages of thermostat-based systems is the wiring required during installation, which can be tricky in open office environments having free-standing work stations and space-dividing partition systems. A major disadvantage of building-wide HVAC computer monitoring systems is that the temperature set point adjustments must be made from a central monitoring station. Thus, the occupants of the individual offices in the building are not able to provide direct input as to the desired temperature set point for the VAV device effecting their office. Instead, occupants typically communicate with the building central monitoring and adjustment computer by telephone so as to make their wishes known with respect to environmental demands in their office.
It would be highly desirable, therefore, to have an HVAC system suitable for large buildings in which the individual VAV devices are capable of having their temperature set point independently directly adjusted by occupants of the offices through a method other than using wall-mounted thermostats. Thus, the occupants, who know best what environmental conditions are most suited for their office at a given time, would like to have a way of adjusting the HVAC system for their space without having to communicate with, or go through, a central monitoring computer, and without having to go to a wall-mounted thermostat.
Accordingly, it is an object of the present invention to provide a process and apparatus for individual adjustment of the temperature set points of a VAV device located in an occupant's office without affecting other offices and without using a thermostat or having to communicate with a central computer.
It is a further object of the present invention to provide a means for the occupant of a space in the building to easily adjust the temperature set points of the VAV device discharging air into his or her space using equipment commonly available in an office environment.
It is still a further object of the present invention to provide a VAV device adjustment system which is easy to install, is user-friendly, is relatively low in cost and provides a wide range of user flexibility.
The process and apparatus of the present invention have other objects and features of advantage which will become more apparent from, and are set forth in more detail in, the following Description of the Best Mode of Carrying Out the Invention and the accompanying drawings.